Bitch, it's called "lighting". In his second pic, he has more light shining on him, causing his skin to reflect more light and appear brighter.

If you look at his arm in his first pic, you can see a little bit of sunlight coming through the rail, illuminating his arm. Take note of the color of his arm in sunlight. Now look at his second picture where he stands in front of several stage lights and take note of his color again. Compare the two notes you just took, and you'll see that they're identical.

Take a white guy and put him in a dark room where there's no light, and he'll appear black because you don't see any light reflecting off his skin.